Light polarizing viewer for use in connection with stereoscopic pictures



n 0, 1948. E. H. LAND 2,440,104

LIGHT POLARIZING VIEWER FOR USE IN CONNECTION WITH STEREO'SCOPICPICTURES Original Filed March 13, 1942 IN VEN TOR.

Patented Apr. 20, 1948 g UNITED v STATES PATENT OFFICE LIGHT POLARIZINGVIEWER FOR USE IN gglfggCTION WITH STEREOSCOPIC HO- Original applicationMarch 13, 1242, Serial No.

434,567. Divided and this application February 24, 1945, Serial No.579,605

6 Claims. 1

This invention relates to viewing devices, and more particularly toviewing devices such as are described, in combination with theatreadmission tickets, in my-co-pending application Serial No. 434,567,filed March 13, 1942 (now Patent No. 2,416,528, issued February 25,1947), for Combined ticket strip and viewing visor, of which application the present case is a division.

An object of the invention is to provide a viewing device for use inconnection with the viewin of stereoscopic pictures projected inpolarized light.

Other objects of the invention are to provide such a viewing devicewhich comprises a plurality of light-polarizing areas, one positionedbefore each eye of an observer; to provide-such a viewing devicecomprising an optically anisotropic transparent strip folded upon itselfto provide two angularly positioned portions each adapted to form atleast part of an eye-covering portion of the viewer; to provide such aviewing device in which the polarizing axes of the aforesaid areas aresubstantially at right angles to each other; to provide such a device inwhich the said polarizing axes of the polarizing areas are at angles ofapproximately 45 degrees with a line joining the centers of saidareas;to provide such a device which may be used as a viewing device fromeither side without alteration in the stereoscopic effect produced; toprovide such a viewing device as one of a multiplicity of such devicesin a strip or roll thereof; and to provide such a multiplicity ofviewing devices provided therebetween with heavily perforated or scoredsections which enable the viewing devices to be separated from eachother.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises an article of manufacture possessingthe features, properties, and therelation of elements which will beexemplified in the article hereinafter described and the scope of theapplication of which will be.

indicated in the claims.

For a fuller understanding of the invention, reference should be had tothe following detailed description, taken in connection with theaccompanying drawings, wherein:

pictures, has heretofore been suggested. Such systems generally havebeen described in several previously issued United States Letters Patentand are explained in greater detail in the patent to Land and Mahler,No. 2,203,687,1ssued June 11, 1940, for Apparatus employing polarizedlight for the production of stereoscopic images, and in the patent toLand, No. 2,099,694, issued November 23, 1937, for Polarizing opticalsystem. Various forms of devices have been suggested. In one formcircularly polarized light is employed. In another the light rayscarrying each image vibrate at angles of substantially 45 degrees to thehorizontal and at right angles to each other. The present invention isintended for use in connection with both these methods of projection.

In the embodiment of the invention shown in Fig. 1, the strip is made upof a single, fairly heavy, self-supporting sheet or strip oflightpolarizing material to, which may advantageously comprise one ofthelight-polarizing materials sold under the trade name Polaroid." Thepolarizing axis of this material may run lengthwise of the strip i0, asindicated by arrows l2, or it may be perpendicular thereto. The strip isfolded upon itself, as for example along the lines I 4, to provide asuccession of inclined areas II extending substantially at '90 degreesto each other, each area being a light-polarizing area and thepolarizing axes of successive areas being substantially at right anglesto each other. Heavy score lines I! may be provided intermediateadjacent pairs of these polarizing areas so that the strip may beseparated into a plurality of viewing units by tearing along the scorelines. The overlying portions of the strip, for example the portionsadjacent fold lines It, may be adhesively bonded together in any wellknown manner in order to effect a more compact and unitary structure.Under these circumstances, the unit lying between successive score linesIS, with the centers of the inclined areas thereof positioned atsubstantially the average intercoular distance from each other, isadapted to function as a viewing device for stereoscopic are formedrespectively in plane polarized light,

comprising a plurality of viewing devices embodying a different form ofthe invention.

The use of polarized light in connection with the projection and viewingof stereoscopic images, and more particularly in connection with theprojection and viewing of, stereoscopic motion vibrating perpendicularlyto the light carrying the other image, and at 45 degrees to thehorizontal.

In Fig. 2, there is shown a further modification of the inventionwhichis adapted, for example, for use in connection with the projection ofstereoscopic images in circularly polarized light one of the polarizingmaterials sold under the trade name Polaroid, or any other suitablesheet-like light-polarizing material, and it may have its polarizingaxis. positioned preferably either perpendicularly to its length, asshown for example by arrows 22. or parallel with its length.

In Fig. 2, the entire face of the polarizing sheet 20 may be laminatedas shown to a quarter-wave retardation device, for example a strip 24 ofstrained cellulose acetate or quarter-wave Cellophane. Strip 24 shouldbe folded upon itself in the same manner as strip iii in Fig. 1, asindicated by dotted lines 25, or otherwise so arranged that itsprincipal optical direction over one eye of an observer is at an angleof 45 degrees to the axis 22 of polarizing material 20. The principaloptical direction of strip 24 is designated by arrows 28,.

at angles of substantially 90 degrees to each other.

Polarizing sheet 20 is preferably pre-sheetedso that when thequarter-wave strip is bonded thereto, there is centrally disposedbetween alteri adapted to fit over the nose of a person using thedevice, as shown for example at 29 in Fig. 2. It will be understood,moreover, that nose aperture 29 may be of any desired shape besides thatshown, and that. if desired, polarizing sheet 20 may be cut to the sameshape as quarter-wave strips 24 and 21. I

The separate units of the device may be separated from each other bytearing along the heavily scored lines 28 so as to provide a series ofsuccessive viewing devices.

In the form of the device shown in Fig. 2, the elements 20, 24 and 21may be bonded together in ways known to the art, for example where thepolarizer comprises cellulose acetate, with oriented polarizingparticles suspended therein. by applying a common solvent to thesurfaces of the quarter-wave and polarizing materials which are incontact.

It will be understood that in the operation of the device shown in Fig.2, the quarter-wave device which lies on the outer side of sheet 20 actsin conjunction with that sheet to convert the viewing device intocircularly polarizing viewing means suitable for use in 'connection withthree dimensional images formed in clockwise and counterclockwisecircularly polarized light, whereas the quarter-wave device lyingintermediate the polarizing sheet and the eyes of the observer has noeffect upon the function of the device, except to make it useful fromeither side.

It should be noted that a similarly operating device may be made similarto the device shown in Fig. 2, by utilizing for sheet 20 a materialwhich will act as a quarter-wave device, with its principal opticaldirection at right angles to the horizontal. Strip 24, which in thismodification of the invention may comprise a strip of lightsheet 20after having been folded upon itself in the same manner as quarter-wa vestrip 24 in Fig. 2. By laminating a second quarter-wave sheet. such assheet 20 in Fig. 2. to the outer side of polarizing strip 24, the devicemay be made operative from either side.

It will be noted that the viewing devices described may be employed byan observer with either surface adjacent the eyes. for reversal of thedevice, so that the observer looks through the opposite surface, causesno alteration in the relative positions of the axes of the variouselements. The entire device is light, thin, easily handled, easilyassembled, and cheap. There is no need to instruct the user as to howthe device is to be handled,v or how it is to be used, whereas withdevices of the same general type that have heretofore been employed itis possible for the observer to look through the devices from onesurface only without losing the .stereoscopic effect which is desired.

In the modifications of the invention described above there is providedan optically anisotropic sheet or strip, either a polarizer or aquarterwave sheet, which is so folded upon itself as to provide in eachviewer a plurality of angularly positioned areas with theircorresponding axes positioned at substantially 90 degrees to each other,one area being positioned before each eye of a wearer of the device.

Since certain changes may be made in the above article and differentembodiments of the invention could be made without departing from thescope thereof, it is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

What is claimed is:

1. A viewing visor comprising a strip of lightpolarizing material thelongitudinal dimension of which is substantially in excess of the widthdimension, said strip having a transmission axis polarizing material,such as one of the polarizing bearing a predetermined relation to saidlongitudinal dimension and having therein a fold roviding a plurality ofdiverging viewing portions adjacent said fold and also providing aninterconnecting portion for said viewing portions, said interconnectingportion consisting of a section of superimposed layers of said strip,said fold causing said transmission axis in one viewing portion to besubstantially perpendicular to said transmission axis in the otherviewing portion whereby each said viewing portion is adapted to blocksubstantially polarized light transmitted by the other viewing ortion,said viewing portions being separated from each other by substantiallythe average interocular distance, said viewing visor being characterizedby the fact that either face thereof may be used as the viewing facewithout alteration of the stereoscopic effect produced.

2. A viewin visor comprising a strip of lightpolarizing material thelongitudinal dimension of which is substantially in excess of the widthdimension, said strip having a transmission axis parallel with saidlongitudinal dimension and having therein a fold providing a pluralityof diverging viewing portions adjacent said fold and also providing aninterconnecting portion for said viewing portions, said interconnectingportion consisting of a section of superimposed layers of said strip,said fold causing said transmission axis in one viewing portion to besubstantially perpendicular to said transmission axis in the otherviewing portion whereby each said viewin portion is adapted to blocksubstantially polarized of which is substantially in excess of the width10 tially perpendicular to said transmission axis in the other viewingportion whereby each said viewing portion is adapted to blocksubstantially polarized light transmitted by the other viewing portion,said viewing portions being separated from each other by substantiallythe average interocular distance, said viewing visor being characterizedby the fact that either face thereof may be used as the viewing facewithout alteration of the stereoscopic effect produced.

4. A viewing visor comprising, in combination, 3)

a strip of light-polarizing material the longitudinal dimension of whichis substantially in excess of the width dimension, said strip having atransmission axis bearing a predetermined relation. to

said longitudinal dimension and having therein a fold providing aplurality of diverging viewing portions adjacent said fold and alsoproviding an interconnecting portion for said viewing portions, saidinterconnecting portion consisting of a section of superimposed layersof said strip, said fold causing said transmission axis in one viewingportion to be substantially perpendicular to said transmission axis inthe other viewing portion. a sheet of transparent quarter-wave materialso superimposed upon and afllxed to said lightpolarizing strip that theprincipal optical direction of said quarter-wave sheet is positioned atan angle of substantially 45 degrees to each of said transmission axes,and a second, similar,

transparent, quarter-wave sheet superimposed upon and affixed to thesurface of said lightpolarizing strip opposite that'to which thefirstmentioned quarter-wave sheet is affixed, said light-polarizingstrip and one of said quarterwave sheets cooperating to circularlypolarize a beam of light transmitted by said viewing portions, saidviewing portions being separated froin each other by substantially theaverage interocular distance, said viewing visor being characterlzed bythe fact that either face thereof may be used as the viewing facewithout alteration of the stereoscopic effect produced.

5. A' viewing visor comprising, in combination, a strip oflight-polarizing material the longitudinal dimension of which issubstantially in excess of the width dimension, said strip having atransmission axis parallel with said longitudinal dimension and havingtherein a fold providing a plurality of diverging viewing portionsadjacent said fold and also providing an interconnectingportion for saidviewing portions, said interconnecting portion consisting of a sectionof superimposed layers of said strip, said fold causing saidtransmission axis in one viewing portion to be substantiallyperpendicular to said transmission axis in the other viewing portion, asheet of transparent quarter-wave material so superimposed upon andaffixed to said light-polarizing strip that the principal opticaldirection of said quarter-wave sheet is positioned at an angle ofsubstantially 45 degrees to each of said transmission axes. and asecond, similar, transparent, quarter-wave sheet superimposed upon andaffixed to the surface of said light-polarizing strip opposite that towhich the first-mentioned quarter-wave sheet is affixed, saidlight-polarizing strip and one of said quarter-wave sheets cooperatingto circularly polarize a beam of light transmitted bysaid viewingportions, said viewin portions being separated from each other bysubstantially the average inter-ocular distance. said viewing visorbeing characterized by the fact that either face thereof may be used asthe viewing face without alteration of the stereoscopic effect produced.

6. Aviewing visor comprising, in combination, a strip oflight-polarizing material the longitudi nal dimension of which issubstantially in excess of the width dimension, said strip having atransmission axis perpendicular to said longitudinal dimension andhaving therein a fold providing a plurality of diverging viewingportions adjacent said fold and also providing an interconnectingportion for said viewing portions, said interconnecting portionconsisting of a section ofsuperimposed layers of said strip, said foldcausing said transmission axis in one viewing portion to besubstantially perpendicular to said transmission axis in the otherviewing portion, a sheet of transparent quarter-wave material sosuperimposed upon and affixed to said light-polarizing strip that theprincipal optical direction of said quarter-wave sheet is positioned atan angle of substantially 45 degrees to each of said transmission axes,and a second, similar, transparent,

quarter-wave sheet superimposed upon and REFERENCES vCITED The followingreferences are of record file of this patent:

' UNITED STATES PATENTS in the Number Name Date 2,099,694 Land Nov. 23,1937 2,218,875 Parsell Oct. 22, 1940 2,285,792 Bailey June 9, 19422,313,831 Martin Mar. 16, 1943 2,323,518 Cochran July 6, 1943 2,337,617Miller Dec. 28. 1943 FOREIGN PATENTS Number Country Date 517,924 GreatBritain Feb. 13, 1940 834,855 France Sept. 5, 1938 841.943

France Feb. 20, 1939

